President Barack Obama, in a speech, called on Israel to return to some variation of its pre-1967 borders.

The practical significance of these and other diplomatic evolutions in relation to Israel is questionable. Historically, U.N. declarations have had variable meanings, depending on the willingness of great powers to enforce them. Obama’s speech on Israel, and his subsequent statements, created enough ambiguity to make exactly what he was saying unclear. Nevertheless, it is clear that the diplomatic atmosphere on Israel is shifting.

There are many questions concerning this shift, ranging from the competing moral and historical claims of the Israelis and Palestinians to the internal politics of each side to whether the Palestinians would be satisfied with a return to the pre-1967 borders. All of these must be addressed, but this analysis is confined to a single issue: whether a return to the 1967 borders would increase the danger to Israel’s national security. Later analyses will focus on Palestinian national security issues and those of others.

Early Borders

It is important to begin by understanding that the pre-1967 borders are actually the borders established by the armistice agreements of 1949. The 1948 U.N. resolution creating the state of Israel created a much smaller Israel. The Arab rejection of what was called “partition” resulted in a war that created the borders that placed the West Bank (named after the west bank of the Jordan River) in Jordanian hands, along with substantial parts of Jerusalem, and placed Gaza in the hands of the Egyptians.

The 1949 borders substantially improved Israel’s position by widening the corridors between the areas granted to Israel under the partition, giving it control of part of Jerusalem and, perhaps most important, control over the Negev. The latter provided Israel with room for maneuver in the event of an Egyptian attack — and Egypt was always Israel’s main adversary. At the same time, the 1949 borders did not eliminate a major strategic threat. The Israel-Jordan border placed Jordanian forces on three sides of Israeli Jerusalem, and threatened the Tel Aviv-Jerusalem corridor. Much of the Israeli heartland, the Tel Aviv-Haifa-Jerusalem triangle, was within Jordanian artillery range, and a Jordanian attack toward the Mediterranean would have to be stopped cold at the border, since there was no room to retreat, regroup and counterattack.

For Israel, the main danger did not come from Jordan attacking by itself. Jordanian forces were limited, and tensions with Egypt and Syria created a de facto alliance between Israel and Jordan. In addition, the Jordanian Hashemite regime lived in deep tension with the Palestinians, since the former were British transplants from the Arabian Peninsula, and the Palestinians saw them as well as the Israelis as interlopers. Thus the danger on the map was mitigated both by politics and by the limited force the Jordanians could bring to bear.

Nevertheless, politics shift, and the 1949 borders posed a strategic problem for Israel. If Egypt, Jordan and Syria were to launch a simultaneous attack (possibly joined by other forces along the Jordan River line) all along Israel’s frontiers, the ability of Israel to defeat the attackers was questionable. The attacks would have to be coordinated — as the 1948 attacks were not — but simultaneous pressure along all frontiers would leave the Israelis with insufficient forces to hold and therefore no framework for a counterattack. From 1948 to 1967, this was Israel’s existential challenge, mitigated by the disharmony among the Arabs and the fact that any attack would be detected in the deployment phase.

Israel’s strategy in this situation had to be the pre-emptive strike. Unable to absorb a coordinated blow, the Israelis had to strike first to disorganize their enemies and to engage them sequentially and in detail. The 1967 war represented Israeli strategy in its first generation. First, it could not allow the enemy to commence hostilities. Whatever the political cost of being labeled the aggressor, Israel had to strike first. Second, it could not be assumed that the political intentions of each neighbor at any one time would determine their behavior. In the event Israel was collapsing, for example, Jordan’s calculations of its own interests would shift, and it would move from being a covert ally to Israel to a nation both repositioning itself in the Arab world and taking advantage of geographical opportunities. Third, the center of gravity of the Arab threat was always Egypt, the neighbor able to field the largest army. Any pre-emptive war would have to begin with Egypt and then move to other neighbors. Fourth, in order to control the sequence and outcome of the war, Israel would have to maintain superior organization and technology at all levels. Finally, and most important, the Israelis would have to move for rapid war termination. They could not afford a war of attrition against forces of superior size. An extended war could drain Israeli combat capability at an astonishing rate. Therefore the pre-emptive strike had to be decisive.

The 1949 borders actually gave Israel a strategic advantage. The Arabs were fighting on external lines. This means their forces could not easily shift between Egypt and Syria, for example, making it difficult to exploit emergent weaknesses along the fronts. The Israelis, on the other hand, fought from interior lines, and in relatively compact terrain. They could carry out a centrifugal offense, beginning with Egypt, shifting to Jordan and finishing with Syria, moving forces from one front to another in a matter of days. Put differently, the Arabs were inherently uncoordinated, unable to support each other. The pre-1967 borders allowed the Israelis to be superbly coordinated, choosing the timing and intensity of combat to suit their capabilities. Israel lacked strategic depth, but it made up for it with compact space and interior lines. If it could choose the time, place and tempo of engagements, it could defeat numerically superior forces. The Arabs could not do this.